Chemical process

Abstract

An improved process for the production of sodium salicylate and salicylic acid from phenol at a high degree of conversion with a concomitant reduction in undesirable by-products. The process comprises reacting a sodium phenolate with carbon dioxide in a direct, single step at a temperature above about 165° C. to produce directly sodium salicylate, which is then converted by conventional means to the salicylic acid.

What is claimed is: 
     
       1. A process for preparing sodium salicylate which comprises reacting phenol with an aqueous solution of sodium hydroxide in a reaction zone to form sodium phenolate; heating the resulting reaction product mixture at elevated temperatures, which are raised to above about 175° C., to remove water therefrom; introducing carbon dioxide into the reaction zone while the thus produced sodium phenolate is maintained at an elevated temperature above about 175° C., and producing sodium salicylate directly in a single step by reaction between the sodium phenolate and carbon dioxide at said elevated temperatures. 
     
     
       2. The process of claim 1 wherein said reaction temperature and the temperature at which the carbon dioxide is introduced is within the range of about 180° to 220° C. 
     
     
       3. The process of claim 1 wherein said reaction zone is a mixer and kneader device comprising counteracting blades to ensure thorough mixing of the phenol, sodium hydroxide, sodium phenolate, and carbon dioxide reactants throughout the process. 
     
     
       4. In a process for the production of salicylic acid comprising sequentially reacting phenol with an aqueous solution of sodium hydroxide in a reaction zone to form sodium phenolate, contacting carbon dioxide with said sodium phenolate to form sodium salicylate, and then acidifying said sodium salicylate to form salicylic acid; the improvement which comprises contacting the carbon dioxide with the sodium phenolate at a reaction temperature of above about 175° C. to reduce substantially the formation of by-product sodium salts of non-salicylic acids. 
     
     
       5. In the process of claim 4 wherein said reaction temperature and the temperature at which the carbon dioxide contacts the sodium phenolate is within the range of about 180° to 220° C. 
     
     
       6. In the process of claim 4 wherein said reaction zone is a mixer and kneader device comprising counteracting blades to ensure thorough mixing of the phenol, sodium hydroxide, sodium phenolate, and carbon dioxide reactants throughout the process.